MATMUL fails in checking arguments shapes

It seems to me that the shapes of MATMUL arguments are not checked for conformability if some of them is an allocatable array.
The consequent result are clearly wrong.

Here is a short example, in which the two arguments are clearly non conformable, being one a 1-by-1 array and the other a 5-by-5 array.
Nevertheless, neither at compile-time (that's understandable) nor at runtime there is a complain when performing MATMUL.

That does not change if the arrays are allocated explicitly.

Note that when compiled using gfortran (I used version 4.9.2) a runtime error is issued.

Did I miss some specific compiling option ?
Is it left to the programmer to ensure arguments conformability ?

The compiler is not obligated by the standard to find such a mismatch in shapes. It is a quality of implementation though. Nagfor (which is considered to be a very good analysing/debugging compiler gets it when compiled with -C=all):